Ion exchange polymers are useful in many industrial fields such as electrical engineering, electronics, semiconductors, precision engineering, food industries, medicine, nuclear power and water treatment.
Conventional ion exchange resins include styrene-divinyl benzene copolymer, acrylic acid- or methacrylic acid-divinyl benzene copolymer.
As conventional ion exchange fibers, conjugate fibers, in which a polymer of aromatic monovinyl compounds constitutes a sheath component, are used as base fibers, as disclosed in Japanese Published Patent Application (Kokai) No. 186/1974, Japanese Published Patent Application (Kokai) No. 94,233/1975, Japanese Published Patent Application (Kokai) No. 12,985/1977 and Japanese Published Patent Application (Kokai) No. 120,986/1977. Other conventional techniques involving melt spun fibers of styrene-divinyl benzene copolymer are disclosed in Japanese Published Patent Application (Kokai) No. 81,169/1973.
Dry spun fibers of baked polyvinyl alcohol are disclosed in Japanese Published Patent Application (Kokai) No. 71,815/1980 and Japanese Published Patent Application (Kokai) No. 184,113/1987, and acrylonitrile fibers are disclosed in Japanese Published Patent Application (Kokai) No. 50,032/1980.
In the prior art, however, with a thermoplastic polymer for manufacturing fibers the melt fluidity is reduced very much in proportion to the increasing cross-linking of the thermoplastic polymer. In this case, therefore, it is impossible to use the usual extruder, but it is necessary to use a very high pressure specific extruder for manufacturing such fibers.
Further, baked polyvinyl alcohol fibers or the like are hard and fragile, and it is difficult to subject them to the ususal processing of fibers such as carding, webbing, spinning to spun yarns, fabrication, knitting and producing non-woven fabrics, etc.